This study investigates whether number dissimilarities on subject and object DPs facilitate the comprehension of subject-and object-extracted centre-embedded relative clauses in children with Grammatical Specific Language Impairment (G-SLI). We compared the performance of a group of English-speaking children with G-SLI (mean age: 12; 11) with that of two groups of younger typically developing (TD) children, matched on grammar and receptive vocabulary, respectively. All groups were more accurate on subject-extracted relative clauses than object-extracted ones and, crucially, they all showed greater accuracy for sentences with dissimilar number features (i.e., one singular, one plural) on the head noun and the embedded DP. These findings are interpreted in the light of current psycholinguistic models of sentence comprehension in TD children and provide further insight into the linguistic nature of G-SLI.

This study investigates whether number dissimilarities on subject and object DPs facilitate the comprehension of subject-and object-extracted centre-embedded relative clauses in children with Grammatical Specific Language Impairment (G-SLI). We compared the performance of a group of English-speaking children with G-SLI (mean age: 12; 11) with that of two groups of younger typically developing (TD) children, matched on grammar and receptive vocabulary, respectively. All groups were more accurate on subject-extracted relative clauses than object-extracted ones and, crucially, they all showed greater accuracy for sentences with dissimilar number features (i.e., one singular, one plural) on the head noun and the embedded DP. These findings are interpreted in the light of current psycholinguistic models of sentence comprehension in TD children and provide further insight into the linguistic nature of G-SLI.

The Relativized Minimality approach to A'-dependencies (Friedmann et al., 2009) predicts that headed object relative clauses (RCs) and which questions are the most difficult, due to the presence of a lexical restriction on both the subject and the object DP which creates intervention. We investigated comprehension of center-embedded headed object RCs with Italian children, where Number and Gender feature values on subject and object DPs are manipulated. We found that. Number conditions are always more accurate than Gender ones, showing that intervention is sensitive to DP-internal structure. We propose a finer definition of the lexical restriction where external and syntactically active features (such as Number) reduce intervention whereas internal and (possibly) lexicalized features (such as Gender) do so to a lesser extent. Our results are also compatible with a memory interference approach in which the human parser is sensitive to highly specific properties of the linguistic input, such as the cue-based model (Van Dyke, 2007).